In an internal combustion engine comprising a supercharger, which has been conventionally known, respective exhaust valves of cylinders are opened sequentially, and exhaust with high pressure is emitted to an exhaust passage from a cylinder whose exhaust valve is opened. Thereby, exhaust pulsation (periodic fluctuation of an exhaust pressure) arises. However, for example, when an exhaust flow rate is small, a peak value (maximum value) of the exhaust pressure accompanied by the exhaust pulsation decreases. When the peak value of the exhaust pressure is small, a turbine cannot be driven sufficiently, and it becomes impossible for the supercharger to perform sufficient supercharging.
Therefore, one of conventional EGR control devices is configured to close an EGR valve when amplitude of exhaust pulsation (difference between a maximum value and a minimum value of an exhaust pressure within one period of exhaust pulsation) is small. As a result of this, since “volume of a region where pressure of exhaust discharged from a combustion chamber immediately propagates (which will be referred to as “exhaust volume” hereafter)” decreases, a peak value of an exhaust pressure accompanied by exhaust pulsation can be avoided from falling excessively. Therefore, also in such a case, supercharging can be performed (refer to the Patent Document 1 (PTL1), for example).